Install the Chisel mod and the Rechiseled mod
Launch Minecraft with the correct mod loader
Gather blocks that support chiseling or rechiseling
Open your inventory
Place the block you want to modify in the Chisel or Rechiseled interface
Select the desired block pattern or variant
Apply the change to convert the block into the chosen style
Use the chisel tool if required by the mod version
Use the crafting grid or block interface if the mod version supports it
Repeat the process for other blocks
Mix and match variants to build custom structures